Hard disk drives (“HDDs”) are widely used to store digital data or electronic information for enterprise data processing systems, computer workstations, portable computing devices, digital audio players, digital video players, and the like. Generally, HDDs store data on a disk with a layer of magnetic material. A transducer head, e.g., read-write head, includes a writing component that magnetically polarizes areas or bits of the magnetic material with one or two polarities to encode either binary zeros or ones. Thus, data is recorded as magnetically encoded areas or bits of magnetic polarity. The direction of the magnetization points in different directions, which can be referred to as a positive state and a negative state. Each bit can store information (generally binary information in the form of either a 1 or a 0) according to the magnetic polarization state of the bit. Typically, bits are arranged along respective radially-adjacent (e.g., concentric) annular tracks of a disk. A single disk can include space for millions of tracks each with millions of bits. A transducer head also includes a reading component that detects the magnetic polarity of each bit or area and generates an electrical signal that approximates the magnetic polarity. The signal is processed to recover the binary data recorded on the magnetic material.
The disks of an HDD rotate as transducer heads hover over the respective disks to read data from and write data to the disks. Many conventional HDD disks include one or more layers of magnetic material applied over a substrate. In addition to the magnetic material, certain HDD disks also include magnetic conditioning sub-layers that stabilize the magnetic polarity of each magnetic bit and otherwise improve the functionality of the HDD. However, the magnetic material and/or the magnetic conditioning sub-layers may react with the substrate, or at least with trace impurities in the substrate, and may produce corrosion byproducts. These corrosion byproducts not only compromise the integrity and stability of the magnetic material, the corrosion byproducts may also migrate to the surface of the HDD disk, thus potentially causing read-write head crashes and/or sticking, which adversely affects the overall operation of the HDD.